Question

Find all the four angles of a cyclic quadrilateral ABCD in
which...
angleA=(x+y+10)..
angle B=(y+20)..
angle C=(x+y-30)...
and angle D=(x+y)...This is easy solve fast..​

Answer 1

Answer:

We know that the sum of the opposite angles of a cyclic quadrilateral is 180

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. In the cyclic quadrilateral ABCD, angles A and C and the angle B and D form pairs of opposite angles.

∴∠A+∠C=180

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and ∠B+∠D=180

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⇒2x−1+2y+15=180

and y+5+4x−7=180

⇒2x+2y=166

and 4x+y=182

⇒x+y=83 ..(i)

and, 4x+y=182 ..(ii)

Subtracting equation (i) from equation (ii), we get

3x=99⇒x=33

Substituting x=33 in equation (i), we get y=50

Hence, ∠A=(2×33−1)

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=65

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,∠B=(y+5)

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=(50+5)

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=55

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∠C=(2y+15)

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=(2×50+15)

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=115

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and ∠D=(4×33−7)

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=125

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.